Why is graphite more stable than diamond?
Diamonds and graphite are both allotropes of carbon, but the differences between the two are very distinct. Out of the two materials, graphite is more stable and less reactive than diamond. Graphite has a number of physical and chemical properties that makes it more stable than diamond.
1. Physical Properties:
- Formation: Diamonds form under very high pressure and temperature whereas graphite requires low pressure and temperature. This makes graphite more stable.
- Shape & Structure: Diamonds have a cubic crystal structure whereas graphite has a hexagonal crystal structure. This makes graphite more flexible and less vulnerable to cracking or breaking.
- Hardness: Diamonds are one of the hardest substances and are very difficult to destroy. This means that diamonds are not very stable. On the other hand, graphite is relatively soft and can be easily damaged, therefore graphite is more stable.
2. Chemical Properties:
- Oxidation: Graphite is highly resistant to oxidation while diamonds burn if heated to high enough temperatures. This makes graphite more stable than diamond.
- Chemical Reactivity: Graphite is much less reactive than diamond, meaning it is more stable. Diamonds are made of carbon atoms, held together by strong chemical bonds which can be broken down easily by other chemicals. Graphite however is held together by weaker bonds, so it is much less likely to react.
In conclusion, graphite is more stable than diamond because of its physical and chemical properties. Graphite has a lower formation temperature and pressure, a hexagonal crystal structure, is more flexible and less vulnerable to breaking, is highly resistant to oxidation and has weaker chemical bonds which makes it less likely to react.
5. Are there other factors that contribute to graphite being more stable than diamond?
Yes, there are several other factors that may contribute to graphite’s stability compared to diamond. Graphite has a greater elasticity than diamond, and it is less brittle and less prone to cracking. Graphite also possesses a lower specific gravity than diamond, meaning it will float in liquids making it easier to transport. Graphite also has a lower energy of formation, meaning less energy is needed to form and shape it. Graphite is also softer and less resistant to scratching, making it easier to shape and polish. Finally, because of its layered structure, graphite can undergo oxidation, which allows for some of the layers to be sacrificial, helping to protect the core structure from further damage.
2. Does graphite have higher covalent bonding than diamond?
No, graphite and diamond both have the same strong covalent bonding that is characteristic of carbon, as both are composed of only carbon atoms.
3. How does the carbon-carbon bond strength differ in graphite and diamond?
The carbon-carbon bond strength in graphite is weaker than in diamond. In diamond, each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral arrangement, resulting in a strong, stable and rigid structure that gives diamond its high hardness. In graphite, the carbon atoms are arranged in sheets of interconnected six-member rings, a much weaker arrangement than in the diamond structure. This results in the weaker carbon-carbon bond in graphite.